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CURRIE April 1933.

SEWER PIPE Original Filed Aug. 2, 1929 c Wf W Cay 7" WM Q2 5 ReissuedApr. 4, 1933 UNITED STATES PATENT OFFICE CLARE H. CURRIE, OF WEBSTERCITY, IOWA, ASSIGNOIBI, BY MESNE ASSIGNMENTS, FIFO L. E. ARMSTRONGREALTY &INVESTMENT 00., 0F FORT DODGE, IOWA, A CORPORA- TION OF IOWASEWER PIPE Original No. 1,834,603, dated December 1, 1931, Serial No.383,005, filed August 2, 1929. Application for reissue filed January 13,1933. SeriaLNo. 651,501.

This invention relates to improvements in sewer pipe, and moreparticularly to pipe or pipe lines used in large sewage handling anddisposal systems and method of constructing the same. I

By alluding to pipe for sewage systems of large capacity, a distinctionis made between the precast vitrified clay pipe used for laying smallsewage pipe lines and those of large dimensions which are usually madecontinuous and of concrete moulded in forms erected in the trench orexcavation. For sewage conveying, however, it is es:- sential to protector cover the surface of concrete pipe lines from the destructive andcorrosive action of the acid constituents of the sewage being handled,and therefore it is common practice to line the inner surface ofconcrete pipe with a non-corrosive material, such as vitrified clay. I

In the present disclosure this lining has the form of thin segmentalplates called liners, and the purpose of the'invention is .to provide animproved. method for anchoring the liners to the surrounding concretebody of the pipe, and further to provide a method of construction forpipe lines which will insure the sealing of the inner lining to thepassage of gases to the'concrete and otherwise lend itself to theerection of continuous poured concrete pipe lines as dist' guished frompre-cast' pipe sections, although the latter is also contemplated. I

A preferred embodiment of .my invention is disclosed in the accompanyingdrawing, in which i Figure 1 is a view in cross section of a sewer pipeconstructed in accordance with .my invention;

Figure 2 1s a view in longitudinal section through the plpe as taken online 2-2 of Figure 1;"

Figure liner, and r a Figure 4 is an-enlarged detail view in crosssection of the pipe at one of the lugs, showing the several forms thatmay be used.

As clearly shown in Figure 1, the pipe is cylindric in shape and of therequired diameter and thickness, and consisting of an out- 3 is aperspective view of a single er layer or shell 1 of concrete and aninner layer or lining of vitrified clay'2, made up of a multitude ofpre-cast segmentsor CHIVlIlH-Q ear plates '3 joined with each other bylap j oints at their four edges. The concrete outer shell isconsiderably thicker than the inner lining, in fact, the thickness ofthe lining not a vital factor as its function is primarily that of aprotective coating for the inside of the pipe.

Each liner or segmental plate is rectangu lar in shape, either square,or elongated in one direction, as desired, but curved on an arcof acircle corresponding to theinternal diameter of the pipe. As shown inFigure 3,

each liner is slightly longer in the direction of the pipe, and at oneend (left) there is an ofi'set flange or lip 3a similar to thebellshaped flange at the end of the ordinary pre-cast sewer pipe. Theopposite end of the liner is plain, a joint or overlap being made withthe forward end of an adjacent plate having the same lip 3a, the lapoccurring on theoutside of the liners so that the inner surface isperfectly smooth.

The side edges f each plate are cast to provide square shoulders 36, 3bof a depth one-half the thickness of the liner and a width about twicethe thickness. These shoulders, however, face in opposite directions,one outwardly and the other inwardly,

The shouldered side edges of each plate joins with plates on eitherside, the upwardly facing shoulder ofone overlapping or interfittingwith the outwardly facing shoulder of r,

the next and so on, entirely around one circular row or course of-platesor liners as shown Figure 1. Each circular row of liners may not,however, register with those of the next, but may be preferablystaggered so that the longitudinal joints between the liners of onecircular course fall between the joints of the courses on either side,as'in Figure 2.

And, finally, each liner has one ormore holes 4 cored through italong'the'longitudinal center line. As shown (Figure '3), there are twoof such holes provided, one being spacedinwardly from each end aboutone-fourth the length ofthe liner; On the inner face of the liner theseholes are counter-sunk.

These liners are moulded or cast of clay and then fired in the samemanner that pipe and other vitrified products are made, so

that their exterior surfaces present the same hard glazed finish commonto such prodiu' o I The preferred method of constructing a pipe line,incorporating the liners, will be understood from the following: Twocylindric forms A and B of suitable length would be used, one'for theinside and the other for ofthe liners. These lugs have theshape of pinsor bolts with a flat conical headat one end of a round shank, and arepreferably made ofsome non-corrosive metal such as Monel metal (a nickelalloy) or other suitable material. The .holes in the liners are sized toreceive the lugs with a snug fit, the

I. heads seating. flush in the countersunk recesses on the inner facesofthe liners and the shank extending through and beyond the outersurfaces thereof, to be eventually embedded in the concrete outer shellor layer.

Consequently, the length of the lugs is governed by the distance theyshould extend into the concrete to provide a firm anchorage, and, ifdesired, notches may be formed 1 along the shank, as shown in Figure 4,to

increase the holding capacity ofthese lugs. Other modifications in the,lugs will be later noted. Y 3 3 Having erected the lining about theinner form with the lugs in place, the entire outer surface of .thelining 2 is then coated .or sprayed with a sealingcompound, such as 1asphaltum, tar. or other suitable substance whichis not aflfected bythe: destructive acid gases in the sewage This coating serves not onlyto fill in and seal the joints and crevices between liners and betweenthe lugs and the holes, but provides an intermediate protective layerzfibetween the inner lining and the outer body of concrete.

The lining having thus been erected and sealed, the outer form B is thenplaced aroundthe inner form and the concrete poured in the usual mannerand allowed to set and harden. The forms, which would be-ofsectionaldesign, are then removed and the same operation repeated for the nextsection of the pipe.

Thepipe so constructed would thus have an inner lining of'yitrifiedclay, an intermediate layer of sealing compound, and an outer shell orlayer of concrete in which are firmly embedded the ends of the lugswhich anchor the lining to the concrete structure of the pipe.

One of thechief advantages of this method of construction is the use ofthe separate lugs inserted through cored holes in the liners, ascompared for instance, with ribs, beads, grooves orother anchoringdevices cast on the outer face of the liners for the purpose ofaffording an anchorage in the concrete. In the manufacture of theliners, the ease of drawing them from the moulds determines the shapeand arrangement of these integral anchoring devices. As a result, ananchoring projection which is suitable from a manufacturing standpointis not generally practical in the construction of the sewer pipefonaccount of the difiiculty in obtaining a perfect anchorage in theiconcrete, due to the fact that in pouring the concrete it does not fillin completely around the projections, but leaves pockets or voids whichweaken the pipe structure, this being particularly true where theprojections extend longitudinally of the liners. With the use of theseparate lugs, however, it is only necessary tocore holes through theplates, thereby materially simplifying the manufacture of the liningmaterial. Again,-

the lugsmay be made of a material more suitable for anchoring purposesthan that of the liner itself, such as metal, and their shape is suchthat the concrete readily flows between and around them so that theybecome firmly embedded. Moreover, separate anchoring members permit ofvariation in their length and shape, to meet different operatingconditions. For'instance, the shanks of the lugs may be lengthened toextend I through the concrete shell, with their projecting ends 56threaded to receive locking members or threaded extensions provided atboth ends, as shown in dotted lines (Figure 4), andwhich can be used forsupporting the formsif the contractor desires,

c Having set forth a preferred embodiment of my invention, I claim:

1. Asewer pipe comprising an outer shell .of 'cementitiousmaterial, aprotective lining for the interior of said shell consisting ofplate-like sections laid edge to edge, a layer'of a sealing compoundinterposed between said outer shell and lining and anchoring membersinserted through holes in said plates and embedded injsaid shell.

2. A sewer pipe'comprising an outer shell of cementitious material, arelative thin intermediate layer of an initially plastic sealingcompound and an inner lining consist- .ing of plates of a corrosionresistant material laid edge toedge and anchoring members adapted to beinserted through holes in said plates from the interior of said pipefastened in said outer shell.

3. A sewer'pipe comprising an outer cylindric shell of relatively thickconcrete, a thin layer of a non-corrosive sealing compound covering theinner surface of said shell, an inner lining consisting of thin platesof a vitreous substance joined edge to edge, and anchor membersconsisting of pins of non-corrosive material passing through holes insaid plates with their shank portions embedded radially in said outershell.

4. A sewer pipe comprising an outer cylindric shell of relatively thickconcrete, a thin layer of a non-corrosive sealing compound covering theinner surface of said shell, an inner vitreous lining of relatively thinplates adapted to be laid edge to edge and having holes therethrough,and anchoring members consisting of pins of a non-corrosive metaladapted to be inserted through the holes in said plates from the insideof the pipe and their shank portions embedded in said outer shell.

Signed at Fort Dodge, Iowa, this 12th day of December, A. D. 1932.

CLARE H. CURRIE.

